CN117577411A

CN117577411A - Linearly actuated magnetic coupling

Info

Publication number: CN117577411A
Application number: CN202311665361.3A
Authority: CN
Inventors: 大卫·H·莫顿; P·J·卡普; S·N·费尔顿
Original assignee: Magnetic Conversion Technology Co ltd
Current assignee: Magnetic Conversion Technology Co ltd
Priority date: 2018-10-24
Filing date: 2019-10-24
Publication date: 2024-02-20
Also published as: KR20210080502A; MX2021004406A; US20220045594A1; EP3857575A1; CN113039619B; WO2020086791A1; EP3857575A4; CN113039619A; JP2022505655A

Abstract

The present disclosure relates to magnetic coupling devices. More specifically, the present disclosure relates to a magnetic coupling apparatus for magnetically coupling with a ferromagnetic workpiece, comprising: a housing having a channel defining a channel axis; a magnetic disk supported by the housing, the magnetic disk being movable along the channel axis between a first position and a second position, the magnetic disk including a plurality of permanent magnet portions interposed between a plurality of ferromagnetic pole piece portions; a workpiece contact interface supported by the housing and adapted to contact a ferromagnetic workpiece; and a magnetic shunt supported by the housing and magnetically accessible from the channel, wherein a first magnetic circuit is formed by the magnetic disk and the magnetic shunt with the magnetic disk in a first position and a second magnetic circuit is formed by the magnetic disk and the ferromagnetic workpiece across the workpiece interface with the magnetic disk in a second position.

Description

Linearly actuated magnetic coupling

The present application is a divisional application of PCT application entitled "linearly actuated magnetic coupling", application date 2019, 10 month 24, international application number PCT/US2019/057766, national application number 201980070119.7.

Technical Field

The present disclosure relates to magnetic coupling devices. More particularly, the present disclosure relates to magnetic coupling devices configured to be linearly actuated and de-actuated.

Background

The magnetic coupling device is used for coupling the ferromagnetic workpiece so as to convey the ferromagnetic workpiece from the first position to the second position, hold the ferromagnetic workpiece and/or lift the ferromagnetic workpiece. An exemplary magnetic coupling is a switchable magnetic coupling that may include a magnetic disk that is linearly translatable between an "off" position and an "on" position. When the magnetic disk is in the "on" state, the magnetic coupling device is configured to couple with a ferromagnetic workpiece to perform, for example, lifting operations, material handling, material retention, magnetic latching, or coupling objects to each other, among other applications.

Disclosure of Invention

Embodiments included herein relate to magnetic coupling devices configured to be linearly actuated and de-actuated. Implementations include, but are not limited to, the following examples.

In one example embodiment, a magnetic coupling apparatus for magnetically coupling with a ferromagnetic workpiece includes: a housing having a channel defining a channel axis; a magnetic disk supported by the housing, the magnetic disk being movable along the channel axis between a first position and a second position, the magnetic disk comprising a plurality of permanent magnet portions interposed between a plurality of ferromagnetic pole piece portions; a workpiece contact interface supported by the housing and adapted to contact a ferromagnetic workpiece; and a magnetic shunt supported by the housing and magnetically accessible from the channel, wherein a first magnetic circuit is formed by the magnetic disk and the magnetic shunt with the magnetic disk in a first position and a second magnetic circuit is formed by the magnetic disk and the ferromagnetic workpiece across the workpiece interface with the magnetic disk in a second position.

While multiple embodiments are disclosed, other embodiments of the invention will become apparent to those skilled in the art from the following detailed description, which, however, shows and describes illustrative embodiments of the invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not as restrictive.

Drawings

Fig. 1A illustrates a side cross-sectional view of an exemplary magnetic coupling positioned on a ferromagnetic workpiece in an exemplary first disconnected state.

Fig. 1B shows a front cross-sectional view of the magnetic coupling of fig. 1A.

Fig. 1C illustrates a front view of the magnetic coupling of fig. 1A.

Fig. 2 shows a front cross-sectional view of the magnetic coupling of fig. 1A-1C in a second conductive state.

Fig. 3 shows a front cross-sectional view of the magnetic coupling of fig. 1A-1C in a third conductive state.

Fig. 4 shows an exploded view of the magnetic coupling of fig. 1A-1C.

Fig. 5 shows a top cross-sectional view of the magnetic coupling of fig. 1A-1C in a first position on a ferromagnetic workpiece.

Fig. 6 shows a top cross-sectional view of the magnetic coupling of fig. 1A-1C in a second position on a ferromagnetic workpiece.

Fig. 7-13 are exemplary portions of pole plates that may be incorporated into the magnetic coupling of fig. 1A-1C.

Fig. 14 illustrates a robotic system including the exemplary magnetic coupling of fig. 1A-1C attached as an end of an arm coupler.

Fig. 15 illustrates a top cross-sectional view of an exemplary sensor layout of the magnetic coupling of fig. 1A-1C.

Fig. 16 shows a simplified front view of the magnetic coupling of fig. 1A-1C and without a ferromagnetic workpiece near the magnetic coupling of fig. 1A-1C.

Fig. 17 shows a simplified elevation view of the magnetic coupling of fig. 1A-1C and a ferromagnetic workpiece separated from the magnetic coupling by a first spacing.

Fig. 18 shows a simplified elevation view of the magnetic coupling of fig. 1A-1C and a ferromagnetic workpiece separate from the magnetic coupling.

Fig. 19 shows a simplified front view of the magnetic coupling of fig. 1A-1C tilted from left to right relative to a ferromagnetic workpiece.

Fig. 20 shows a simplified front view of the magnetic coupling of fig. 1A-1C tilted front-to-back relative to a ferromagnetic workpiece.

Fig. 21 shows a simplified front view of the magnetic coupling of fig. 1A-1C contacting a right edge portion of a ferromagnetic workpiece.

Fig. 22 shows a simplified front view of the magnetic coupling of fig. 1A-1C contacting a central portion of a ferromagnetic workpiece.

Fig. 23 shows a simplified front view of the magnetic coupling of fig. 1A-1C in contact with a ferromagnetic workpiece at a first limit position.

Fig. 24 shows a simplified front view of the end of the arm magnetic coupling of fig. 1A-1C in contact with a ferromagnetic workpiece at a second limit position.

While the invention is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail below. However, the invention is not limited to the specific embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims.

Detailed Description

In the drawings and in the foregoing portions of this specification, terms such as "upper," "lower," "axial," and other reference terms are used to facilitate an understanding of the technology described herein, and are not to be considered absolute and limiting reference indicators unless the context indicates otherwise. The terms "coupled," "coupler," and variations thereof are used to include arrangements in which two or more components are in direct physical contact, and arrangements in which two or more components are not in direct contact with each other (e.g., components are "coupled" via at least a third component), but yet still cooperate or interact with each other.

Fig. 1A illustrates a side cross-sectional view of an exemplary switchable magnetic coupling device 100 in a first disconnected state; fig. 1B shows a front cross-sectional view of magnetic coupling 100; and figure 1C shows a front view of the magnetic coupling 100. Fig. 2 shows a front cross-sectional view of the magnetic coupling of fig. 1A-1C in a second conductive state. Fig. 3 shows a front cross-sectional view of the magnetic coupling of fig. 1A-1C in a third conductive state.

The magnetic coupling apparatus 100 may be switched between a first off state (depicted in fig. 1A-1C), a second on state (depicted in fig. 2), and/or a third on state. When the magnetic coupling apparatus 100 is switched to the on state, the magnetic field generated by the magnetic coupling apparatus 100 passes through the one or more ferromagnetic workpieces 102 and couples the magnetic coupling apparatus 100 with one or more of the ferromagnetic workpieces 102. When the magnetic coupling apparatus 100 is switched to the off state, the magnetic field generated by the magnetic coupling apparatus 100 is primarily confined within the magnetic coupling apparatus 100 and, as a result, the magnetic coupling apparatus 100 is no longer coupled with one or more of the ferromagnetic workpieces 102. The off-state and on-state are discussed in more detail below.

The magnetic coupling apparatus 100 may be used as an end of an arm ("EOAMT") unit of a robotic system, such as robotic system 600 (see fig. 14), but may also be used with other lifting, transporting, and/or separating systems for ferromagnetic workpieces 102. Exemplary lifting and transporting systems include robotic systems, mechanical racks, cranes, and additional systems that lift and/or transport the ferromagnetic workpiece 102. In addition, the magnetic coupling apparatus 100 may also be used as part of a fixture for holding at least one portion for operations such as welding, inspection, and other operations.

Referring to fig. 1A, the magnetic coupling apparatus 100 is positioned on top of a ferromagnetic workpiece 102 and includes a workpiece contact interface 104 configured to contact and engage the ferromagnetic workpiece 102. The workpiece contact interface 104 may be a plate 106. In at least one embodiment, the plate 106 includes a plurality of spaced apart protrusions 108, as shown in FIG. 1B. In other embodiments, plate 106 does not include spaced apart protrusions 108. The spaced apart protrusions 108 may facilitate concentrating more magnetic flux near the workpiece contact interface 104 such that when the magnetic coupling 100 is in the on state, the magnetic flux of the magnetic coupling 100 primarily passes through the first ferromagnetic workpiece 102'. Exemplary aspects of plate 106 and protrusion 108 are discussed below.

The magnetic coupling apparatus 100 further includes a housing 110 supporting a magnetic disk 112. When the magnetic coupling apparatus 100 is in the conductive state, the magnetic disk 112 generates a magnetic field that allows the magnetic coupling apparatus 100 to couple with the ferromagnetic workpiece 102. In at least one embodiment, the magnetic disk 112 is a laminated magnetic disk including a plurality of spaced apart permanent magnet portions 114 and a plurality of pole portions 116, as shown in FIG. 1B. Each of the plurality of spaced apart permanent magnet portions 114 includes one or more permanent magnets. In one embodiment, each permanent magnet portion 114 comprises a single permanent magnet. In another embodiment, each permanent magnet portion 114 includes a plurality of permanent magnets. Each permanent magnet portion 114 is fully magnetized and has a north pole side and a south pole side.

Each pole portion 116A is positioned between two of the permanent magnet portions 114, and a pole portion 116B is disposed adjacent to one permanent magnet portion 114. In addition, the permanent magnet portions 114 are arranged such that the north pole side or the south pole side of each of the two permanent magnet portions 114 in contact with the pole portion 116A is in contact with the pole portion 116A. When the north pole side of an adjacent permanent magnet portion 114 contacts the pole portion 116A, the pole portion 116A is referred to as a north pole portion. When the south pole side of an adjacent permanent magnet segment 114 is in contact with pole segment 116A, pole segment 116A is referred to as a south pole segment. Similarly, for pole segment 116B, when the south pole side of permanent magnet segment 114 contacts pole segment 116B, pole segment 116B is referred to as a south pole segment. In contrast, when the north pole side of the permanent magnet portion 114 contacts the pole portion 116B, the pole portion 116B is referred to as a north pole portion.

In the illustrated embodiment, the permanent magnet portions 114 are disposed along a horizontal axis 118. However, in other embodiments, the permanent magnet portions 114 may be arranged in a circular configuration. Further, while the embodiment shows a magnetic disk 112 that includes six permanent magnet portions 114 and seven pole portions 116, other embodiments may include more or fewer permanent magnet portions 114 and pole portions 116. For example, in one embodiment, the magnetic disk 112 may include one permanent magnet portion 114 and two pole portions 116, with one pole portion 116 disposed on each side of the permanent magnet portion 114.

Due to the configuration of the magnetic disk 112 and the magnetic coupling 100, the magnetic flux transfer of the magnetic coupling 100 to one or more of the ferromagnetic plates 102 may be greater than in conventional embodiments. This results in the magnetic coupling apparatus 100 being able to lift more and/or heavier ferromagnetic workpieces 102 per unit magnetic volume included in the magnetic coupling apparatus 100. For example, for a magnetic coupling 100 per cubic millimeter of volume, the retention force of the magnetic coupling 100 may be greater than or equal to 0.35 grams of the ferromagnetic workpiece 102. As another example, the retention force of the magnetic coupling 100 may be greater than or equal to 0.8 grams of the ferromagnetic work piece 102 per cubic millimeter of the housing 110 of the magnetic coupling 100.

To switch the magnetic coupling 100 between the first off-state and the second on-state, the magnetic disk 112 is linearly translatable along the axis 120 within the interior cavity 122 of the housing 110. In an embodiment, the axis 120 is a vertical axis 120. Alternatively, axis 120 is an axis other than a vertical axis. The axis 120 extends between a first end of the housing 110 and a second end of the housing 110. In at least some embodiments, the first end is an upper portion of the housing 110 and the second end is a lower portion of the housing 110, and may be referred to herein as such. However, in at least some other embodiments, the first end is a portion of the housing 110 other than the upper portion of the housing 110, and the second end is a portion of the housing 110 other than the lower portion of the housing 110. When the magnetic disk 112 is disposed adjacent the upper portion 124 of the housing 110, the magnetic coupling 100 is in a first, disconnected state. When the magnetic disk 112 is disposed adjacent the lower portion 126 of the housing 110, the magnetic coupling 100 is in a second conductive state. In addition to the first off-state and the second on-state, the magnetic disk 112 may be disposed at one or more intermediate positions between the upper portion 124 and the lower portion 126, as shown in fig. 3. The intermediate position may be referred to herein as a third conductive state. The third conductive state may generate less magnetic flux at the workpiece contact interface 104 than the second conductive state, as discussed below. For example, the third conductive state may result in a majority of the magnetic flux extending through only the first workpiece 102', such that only a small amount of the magnetic flux extends through the second and third workpieces 102", 102'". As such, the third conductive state may facilitate unstacking the workpiece 102 'from the workpiece 102", 102'", as shown.

To translate the magnetic disk 112 along the vertical axis 120 to transition the magnetic coupling apparatus 100 between the on-state and the off-state and vice versa, the magnetic coupling apparatus 100 includes an actuator 128. In at least one embodiment, the actuator 128 is coupled to the magnetic disk 112 via an interface 130 and a non-ferromagnetic mounting plate 132. That is, the actuator 128 is coupled with an engagement portion 130 that is coupled with a non-ferromagnetic mounting plate 132; and a non-ferromagnetic mounting plate 132 is coupled to and in contact with the magnetic disk 112. The actuator 128 is configured to exert a force on the engagement portion 130 and, in response, the engagement portion 130 translates along the vertical axis 120 to transition the magnetic coupling 100 from the off-state to the on-state, and vice versa. That is, to transition the magnetic coupling apparatus 100 from the off state to the on state, the actuator 128 exerts a downward force on the engagement portion 130 that is transferred to the non-ferromagnetic mounting plate 132 and the magnetic disk 112. In response, the magnetic disk 112 translates from the upper portion 124 to the lower portion 126. Conversely, to transition the magnetic coupling 100 from the on state to the off state, the actuator 128 exerts an upward force on the engagement portion 130 that is transferred to the non-ferromagnetic mounting plate 132 and the magnetic disk 112. In response, the magnetic disk 112 and the non-ferromagnetic mounting plate 132 translate from the lower portion 126 to the upper portion 124.

To place the magnetic disk 112 in the third conductive state, the actuator 128 may generate a force on the engagement portion 130 to translate the magnetic disk 112 from the upper portion 124 to the lower portion 126, and vice versa. Then, as the magnetic disk 112 transitions or reverses from the upper portion 124 to the lower portion 126, a detent 134 disposed within the housing 110 and/or within the actuator 128 may engage the magnetic disk 112, the non-ferromagnetic mounting plate 132, and/or the engagement 130 and stop the magnetic disk 112 in the third conductive state, as depicted in fig. 3.

Exemplary actuators 128 include electric actuators, pneumatic actuators, hydraulic actuators, and other suitable devices that exert a force on the joint 130. An exemplary pneumatic linear actuator is depicted in fig. 4 and discussed in more detail in connection therewith. An exemplary electric actuator is an electric motor having a "deployed" stator and rotor coupled to the interface 130. Other exemplary joints and actuators are disclosed in U.S. patent No.7,012,495 entitled "SWITCHABLE permanent magnet device (switch PERMANENT MAGNETIC DEVICE)", U.S. patent No.7,161,451 entitled "MODULAR permanent magnet CHUCK (MODULAR PERMANENT MAGNET CHUCK)", U.S. patent No.8,878,639 entitled "magnet array (MAGNET ARRAYS)", U.S. provisional patent application No.62/248,804 entitled "magnetic coupling with rotary ACTUATION SYSTEM (MAGNETIC COUPLING DEVICE WITH A ROTARY ACTUATION SYSTEM)", filed on 10 months 30 days 2015 (volume No. MTI-0007-01-US-E), and U.S. provisional patent application No.62/252,435 entitled "magnetic coupling with linear ACTUATION SYSTEM (MAGNETIC COUPLING DEVICE WITH ALINEAR SYSTEM)", filed on 7 months 2015, the entire disclosures of which are expressly incorporated herein by reference.

Additionally or alternatively, the actuator 128 may include a controller 136 and/or a sensor 138A. The controller 136 includes a processor 140 with an associated computer readable medium (illustratively, a memory 142). The memory 142 includes control logic 144 that, when executed by the processor 140, causes the electronic controller 136 to instruct the actuator 128 to move the magnetic disk 112 such that the magnetic coupling apparatus 100 is in the off state, the second on state, and/or the third on state. For example, the sensor 138A may sense the position of the actuator 128 and, in response to a predetermined position sensed by the sensor 138A (which translates into a position of the magnetic disk 112), the control logic 144 instructs the actuator 128 to cease applying a force on the magnetic disk 112 when the magnetic disk 112 reaches a desired position.

In at least one embodiment, the actuator 128 is a stepper motor, and the rotational motion of the actuator 128 is translated into linear motion of the engagement 130 via a coupling (e.g., a gear) between a shaft of the actuator 128 and the engagement 130. In these embodiments, the sensor 138A counts pulses for driving the stepper motor and determines the position of the stepper motor's shaft based on the number of pulses, which is translated into the position of the magnetic disk 112. That is, by counting the number of pulses, the magnetic disk 112 is relatively moved to a defined position along the vertical axis 120 by the step size of the motor movement. In another example, a stepper motor is provided that integrates an encoder with the stepper to check whether the proper actuation angle is maintained.

As another example, the magnetic coupling 100 may include a sensor 138B. The sensor 138B may measure the position of the magnetic disk 112 within the housing 110. Exemplary sensor 138B includes an optical sensor that monitors a reflection band attached to magnetic disk 112. Other sensor systems may be used to determine the position of the magnetic disk 112.

As yet another example, the magnetic coupling 100 may include one or more sensors 138C (shown in fig. 1B). The sensor 138C may be a magnetic flux sensor and is positioned at one or more locations generally above the pole plate 106. Exemplary magnetic flux sensors include hall effect sensors. Sensor 138C measures leakage flux proximate one or more north and south poles of pole plate 106. The amount of leakage flux at each sensor 138C varies based on the position of the magnetic disk 112 relative to the pole plate 106 and the amount of flux through the north and south poles of the pole plate 106, the workpiece contact interface 104 to the ferromagnetic workpiece 102. By monitoring the magnetic flux at a location opposite the workpiece contact interface 104 of the north and south poles of the pole plate 106, the relative position of the magnetic disk 112 can be determined. In an embodiment, the magnetic coupling 100 is positioned on top of the ferromagnetic work piece 102 and the magnetic flux measured by the sensor 138C is recorded as a function of the position of the magnetic disk 112 as the magnetic disk 112 moves from the off state to the second on state. Each of the magnetic fluxes is assigned to a desired position of the magnetic disc 112. An exemplary sensing system with sensor 138C is disclosed in U.S. patent application No.15/964,884, filed on 2018, 4, 27, entitled magnetic coupling (Magnetic Coupling Device with at Least One of a Sensor Arrangement and a Degauss Capability) with at least one of a sensor device and a degaussing function, the entire disclosure of which is expressly incorporated herein by reference.

As yet another example, the magnetic coupling 100 may include one or more sensors 138D (shown in fig. 1A, 1B, 1C, 2, and 3). The sensor 138D may be a magnetic flux sensor and is positioned generally adjacent to the pole plate 106. Exemplary magnetic flux sensors include hall effect sensors. In at least one example, sensor 138D is located near an end of one or more of protrusions 108 of pole plate 106 and measures leakage flux from sides of one or more north and south poles of pole plate 106. The amount of leakage flux at each sensor 138D varies based on the position of the magnetic disk 112 relative to the pole plate 106 and the amount of flux to the ferromagnetic workpiece 102 through the north and south poles of the pole plate 106 and the workpiece contact interface 104. By monitoring the magnetic flux at a location near the pole plate 106, the relative position of the magnetic disk 112 can be determined. In an embodiment, the magnetic coupling 100 is positioned on top of the ferromagnetic work piece 102 and the magnetic flux measured by the sensor 138D is recorded as a function of the position of the magnetic disk 112 as the magnetic disk 112 moves from the off state to the second on state. Each magnetic flux is allocated to a desired location of the magnetic disk 112. U.S. patent application No.15/964,884, filed on 2018, 4, 27, entitled "magnetic coupling (Magnetic Coupling Device with at Least One of a Sensor Arrangement and a Degauss Capability) with at least one of a sensor device and a degaussing function," discloses an exemplary sensing system with a sensor 138D, the entire disclosure of which is expressly incorporated herein by reference.

In at least some embodiments, the magnetic coupling 100 includes a shield 139 (shown in fig. 1A, 1B, 1C, 2, and 3). When the magnetic coupling 100 is in the off position, the shield 139 may absorb magnetic flux from the magnetic disk 112 and reduce the external magnetic field of the magnetic coupling 100. The shielding plate 139 may be formed of a high magnetic saturation material capable of absorbing a large amount of magnetic flux. In one example, the shield 139 is located outside of the housing 110. The top edge of the shield 139 may be planar with the top surface of the magnetic disk 112. Additionally or alternatively, the shield 139 may extend downward along the housing 110 such that a bottom edge of the shield 139 extends beyond the bottom planar surface of the magnetic disk 112. The shield 139 may be located on any side of the magnetic coupling 100. In at least one example, the shield 139 is located on all sides of the magnetic coupling 100. In another example, the shield plate 139A is located only on a face of the magnetic coupling 100 adjacent to an end of the permanent magnet portion 114, as shown in fig. 1A, 1C. In other words, the shield plate 139A may be located on the same side(s) as the sensor(s) 138D. In another example, the shield 139B is located only on the side of the magnetic coupling 100 that extends parallel to the protrusion 108, as shown in fig. 2 and 3.

In an embodiment, the controller 136 changes the state of the magnetic coupling 100 in response to an input signal received from the I/O device 146. Exemplary input devices include buttons, switches, levers, dials, touch displays, pneumatic valves, soft keys, and communication modules. Exemplary output devices include visual indicators, audio indicators, and communication modules. Exemplary visual indicators include displays, lights, and other visual systems. Exemplary audio indicators include speakers and other suitable audio systems. In an embodiment, the apparatus 100 includes a simple visual status indicator in the form of one or more LEDs driven by the processor 140 of the control logic 144 to indicate when a predefined magnetic coupling 100 status is present or absent (e.g., red LED on when the magnetic coupling 100 is in a first off state, green LED flash quickly when the magnetic coupling 100 is in a second on state and ferromagnetic workpiece 102 proximity is detected, green LED flash slowly and yellow LED on when a desired specific area (see discussion regarding fig. 22-24) on the ferromagnetic workpiece 102 is externally contacted (see discussion regarding fig. 22-24), and yellow LED off and stable green LED on, showing the magnetic coupling 100 engaged within threshold limits, showing a safe magnetic coupling status.

For example, in one embodiment, the magnetic coupling apparatus 100 is coupled with an end of an arm of a robotic arm, and the I/O device 146 is a network interface through which the controller 136 receives instructions from the robotic controller regarding when to place the magnetic coupling apparatus 100 in one of a first off state, a second on state, or a third on state. Exemplary network interfaces include wired network connections and antennas for wireless network connections. While the embodiments discussed above relate to electronic, pneumatic, or hydraulic actuation, in alternative embodiments, the magnetic coupling 100 may be manually actuated by an operator.

The magnetic coupling 100 may also include one or more ferromagnetic pieces 148 disposed at or near the upper portion 124 of the housing 100, as shown in fig. 1A. In at least one embodiment, the non-ferromagnetic mounting plate 132 and the ferromagnetic plate 148 are disposed within the housing 110 such that the non-ferromagnetic mounting plate 132 is located between and in contact with the ferromagnetic plate 148 when the magnetic coupling apparatus 100 is in the first, open position. In addition, the top of the magnetic disk 112 may be in contact with the bottom of the ferromagnetic plate 148. In another exemplary embodiment, the ferromagnetic piece 148 may extend downward along the sides of the magnetic disk 112. In these embodiments, the ferromagnetic pieces 148 may reduce leakage of the magnetic disk 112 by additionally absorbing the magnetic field generated by the magnetic disk 112.

In at least one embodiment, the non-ferromagnetic mounting plate 132 may be made of a non-ferromagnetic material (e.g., aluminum, austenitic stainless steel, etc.). In these embodiments, when the magnetic coupling apparatus 100 is in the first disconnected state and the magnetic disk 112 and the non-ferromagnetic mounting plate 132 are positioned at or near the upper portion 118 of the housing 110, one or more circuits are created between the magnetic disk 112, the ferromagnetic piece 148, and the non-ferromagnetic mounting plate 132, as shown in fig. 1B. Furthermore, when the magnetic coupling apparatus 100 is in the first open state, a gap 150 (of fig. 1A) including air and/or another substance having a low magnetic susceptibility in the interior cavity 122 is located between the pole plate 106 and the magnetic disk 112 and separates the pole plate 106 from the magnetic disk 112. Thus, when the magnetic coupling 100 is in the first, open state, little or no magnetic flux from the magnetic disk 112 extends to the workpiece contact interface 104 and through the ferromagnetic workpiece 102. Thus, the magnetic coupling apparatus 100 may be separated from the ferromagnetic workpiece 102. In addition, due to the loop between the magnetic disk 112, the ferromagnetic piece 148, and the non-ferromagnetic mounting plate 132, most, if not all, of the magnetic flux from the magnetic disk 112 is contained within the housing 110.

Another advantage of including ferromagnetic plate 148 is that the distance of gap 150 between the bottom of magnetic disk 112 and pole plate 106 may be less than if magnetic coupling device 100 did not include non-ferromagnetic mounting plate 132 and ferromagnetic plate 148. That is, one or more loops created between the magnetic disk 112, the ferromagnetic plate 148, and the non-ferromagnetic mounting plate 132 facilitate confining a majority, if not all, of the magnetic flux from the magnetic disk 112 within the housing 110, proximate the magnetic disk 112, and distal from the pole plate 106. As such, the magnetic flux transferred to the ferromagnetic workpieces 102 by the magnetic coupling apparatus 100 is insufficient to lift one or more of the ferromagnetic workpieces 102. In other words, the magnetic flux may be effectively zero at the bottom of the pole plate 106, and thus, effectively, the magnetic flux is not transferred to the ferromagnetic work piece 102 by the magnetic coupling device 102, which reduces the overall required height (see height 182 below) that the magnetic disk 112 needs to travel when the magnetic coupling device 102 transitions between the off state and the one or more on states.

Conversely, if the non-ferromagnetic mounting plate 132 and the ferromagnetic plate 148 are not included in the magnetic coupling device 102, less magnetic flux from the magnetic disk 112 will be confined within the housing 110 and/or near the magnetic disk 112. Also, because less magnetic flux will be confined near the magnetic disk 112, the gap 150 between the bottom of the magnetic disk 112 and the pole plate 106 will have to be larger so that the magnetic flux does not extend downward through the pole plate 106 and couple the magnetic coupling device 100 with one or more of the ferromagnetic pieces 102. Because the gap 150 is smaller in the illustrated embodiment, the magnetic coupling 100 may be smaller than other magnetic couplings that do not have these features.

As an example, the gap 150 travelled by the magnetic disk 112 to transition between the first off-state and the second on-state may be less than or equal to 8mm. Conversely, to transition from the second on state to the first off state, the magnetic disk 112 may travel less than or equal to 8mm.

Another advantage of the illustrated embodiment is that, because the gap 150 is smaller, the actuator 128 may use less energy to translate the magnetic disk 112 along the vertical axis 120 within the housing 110. Yet another advantage of the illustrated embodiment is that when the actuator 128 translates the magnetic disk 112 from the first off position to the second on position and the magnetic disk 112 is in contact with the pole plate 106, the magnetic disk 112 will be less likely to break. This is because the magnetic disk 112 builds up less momentum during the transition due to the reduced gap 150. As a further advantage of the illustrated embodiment, in the event that the magnetic coupling apparatus 100 fails while the magnetic coupling apparatus 100 is in an off state, the magnetic coupling apparatus 100 will not transition to an on state due to the non-ferromagnetic mounting plate 132 and the ferromagnetic plate 148. In this way, the magnetic coupling 100 is safer than a magnetic coupling that transitions from an off-state to an on-state when the magnetic coupling fails. In contrast, in the case where the magnetic coupling apparatus 100 does not include the non-ferromagnetic mounting plate 132 and/or the ferromagnetic plate 148, the magnetic disk 112 is more likely to transition to the on state due to the lack of a magnetic circuit generated in the off position.

As described above, when the magnetic disk 112 is positioned at or near the lower portion 126 of the housing 110, the magnetic coupling 100 is in the second conductive state. As shown in fig. 2, when the magnetic coupling 100 is in the second conductive state, the magnetic flux from the magnetic disk 112 extends through one or more of the ferromagnetic workpieces 102. As such, the magnetic coupling apparatus 100 is configured to couple with one or more ferromagnetic workpieces 102 when the magnetic coupling apparatus 100 is in the first conductive state. Although the magnetic flux lines are shown passing through the two ferromagnetic work pieces 102', 102", in some embodiments the magnetic flux lines primarily only pass through the ferromagnetic work pieces 102'. The magnetic coupling 100 may be used to unstack and separate the ferromagnetic workpieces 102 from one another when the magnetic flux lines primarily pass through the first ferromagnetic workpiece 102'.

To facilitate the passage of magnetic flux lines primarily only through the first ferromagnetic work piece 102' when the magnetic coupling apparatus 100 is in the second conductive state, the magnetic disk 112 may be removable and replaceable, which allows magnetic disks 112 of different strengths, heights, and/or widths to be used with the magnetic coupling apparatus 100. The strength, height, and/or width of the magnetic disk 112 may be selected based on the thickness of the ferromagnetic work piece 102 such that the ferromagnetic work pieces 102 may be adequately unstacked and separated from one another when the magnetic coupling apparatus 100 is in the second conductive position.

Additionally or alternatively, the pole plates 106 may be removable and replaceable, which allows different types of pole plates 106 to be used with the magnetic coupling 100. For example, the pole plate 106 may be selected based on the type of ferromagnetic workpiece 102 to which the magnetic coupling apparatus 100 is being coupled. For example, the magnetic coupling 100 may treat a class a surfaces that cannot be scratched or scratched. Thus, a plate 106 of rubber (or another material that reduces the likelihood of scratching or gouging the ferromagnetic workpiece 102) disposed on the workpiece contact interface may be selected and incorporated into the magnetic coupling apparatus 100. As another example, plates 106 having different protrusions and/or gaps may be selected based on the thickness of the ferromagnetic workpiece 102 to which the magnetic coupling apparatus 100 is being coupled. Additional examples of the correlation of the protrusions and/or gaps are explained in more detail below in connection with fig. 7-13.

As discussed in more detail below in connection with fig. 4, the housing 110 is configured in a manner that allows the magnetic disk 112 and/or pole plate 106 to be easily removed and replaced.

Additionally or alternatively, the magnetic coupling 100 may transition to one or more intermediate states as described above. For example, the magnetic coupling apparatus 100 may transition to the third conductive state, as shown in fig. 3. The third conductive state is when the magnetic disk 112 is located along the vertical axis 120 between the position of the magnetic disk 112 when the magnetic coupling 100 is in the first, off state and the position of the magnetic disk 112 when the magnetic coupling 100 is in the second, conductive state. In embodiments using the same magnetic disk 112, less magnetic flux passes through the workpiece contact interface 104 and into the ferromagnetic workpiece 102 when the magnetic coupling apparatus 100 is in the third conductive state than when the magnetic coupling apparatus 100 is in the second conductive state, as shown in fig. 3. That is, assuming that the same strength magnetic disk 112 is used in the embodiment depicted in fig. 2 and 3, the magnetic flux lines in fig. 2 pass through both ferromagnetic workpieces 102', 102", while the magnetic flux lines in fig. 3 pass through only ferromagnetic workpiece 102'. By being able to be in the third conductive state, the magnetic coupling apparatus 100 may be able to unstack ferromagnetic workpieces 102 of different thicknesses without having to replace the magnetic disk 112 with a magnetic disk 112 of different strength.

As described above, plate 106 includes a plurality of protrusions 108. Each protrusion 108 acts as a pole extension for a corresponding pole of pole 116. That is, when magnetic coupling 100 is in the second or third conductive state, the respective north or south pole of pole 116 extends downward through the respective protrusion 108. A magnetic circuit is then created from the N-pole 116 through the corresponding N-pole protrusion 108, through the one or more ferromagnetic pieces 102, through the S-pole protrusion 108, and through the S-pole 116. When the magnetic coupling 100 is in the on-state, each permanent magnet portion creates one of these magnetic circuits. As explained in more detail below in connection with fig. 7-13, the size of the protrusions 108 and the distance therebetween affect the flux transfer of the ferromagnetic workpiece 102 and allow for more efficient unstacking and increased retention of the ferromagnetic material 102. For example, in at least some embodiments, in order to achieve the highest magnetic flux concentration of the ferromagnetic workpiece 102' being transferred through the ferromagnetic workpiece 102 and thus have the greatest likelihood of being able to unstack the ferromagnetic workpiece 102' from the ferromagnetic workpiece 102", 102 '", the size (e.g., width and height) of the protrusions and the gap therebetween should generally match the thickness of the ferromagnetic workpiece 102.

To separate N and S protrusions 108, plate 106 may include slots configured to receive one or more non-ferromagnetic sheets 152 (depicted in fig. 1B). Non-ferromagnetic sheets 152 may be disposed within a respective envelope 154 (depicted in fig. 1B) between each protrusion 108. Because of the non-ferromagnetic plate 152, the magnetic circuit created by the permanent magnet portion 114 does not extend substantially through the non-ferromagnetic plate 152, and therefore, the N and S projections are separated from each other. Further, as described above, protrusion 108 causes magnetic flux from magnetic disk 112 to be closer to workpiece contact interface 104 than if plate 106 did not include a plurality of protrusions 108. Various aspects of facilitating the concentration of magnetic flux from magnetic disk 112 closer to protrusion 108 of workpiece contact interface 104 are discussed below in connection with fig. 7-13.

Referring to fig. 4, an exploded view of the magnetic coupling 100 is shown. As shown, the housing 110 includes a lower portion 110A releasably secured to an upper portion 110B. The lower portion 110A may be secured to the upper portion 110B using one or more screws 156. The screw 156 may allow easy access to components of the magnetic coupling 100 disposed within the housing 110, as explained below.

The lower portion 110A receives the pole plate 106 before connecting the lower portion 110A with the upper portion 110B. In at least one embodiment, the lower portion 110A includes recesses/cutouts 158 configured to receive lugs 160 of the plate 106. The lugs 160 facilitate proper positioning of the plate 106 within the lower portion 110A. In the event that a plate 106 having a different protrusion 108 than the currently installed plate 106 is desired, then proper positioning of the plate 106 may facilitate easy replacement of the plate 106. For example, the lower portion 110A of the housing 110 may be separated from the upper portion 110B by removing the screw 156. The plate 106 may then be removed from the lower portion 110A. Thereafter, another plate 106 having a different protrusion 108 may be inserted into the lower portion 110A such that the lugs 160 are received by the recesses/cutouts 158. Finally, screws 156 may be used to secure the lower portion 110A to the upper portion 110B.

In addition to or in lieu of replacement pole plate 106, the design of magnetic coupling 100 also facilitates easy removal and replacement of magnetic disk 112. For example, as shown, the non-ferromagnetic mounting plate 132 is coupled to the magnetic disk 112 via one or more screws 161. After removing the lower portion 110A from the upper portion 110B, the magnetic disk 112 may be lowered along the vertical axis 120 so that the screw 161 may be accessed. Once the screw 161 is unscrewed, the magnetic disk 112 can be separated from the non-ferromagnetic mounting plate 132 and replaced with another magnetic disk 112. Screws 161 may be used to secure the new magnetic disk 112 to the non-ferromagnetic mounting plate 132. Thereafter, the lower portion 110A and the upper portion 110B may be coupled together using screws 156.

In some cases, replacement of the magnetic disk 112 may be desirable in the event that the magnetic disk 112 breaks or fails. In other examples, it may be desirable to replace the magnetic disk 112 with a magnetic disk 112 that produces a stronger or weaker magnetic field. As discussed above, replacing the magnetic disk 112 with a magnetic disk 112 having a stronger or weaker magnetic property may facilitate unstacking the ferromagnetic workpiece 102. For example, the first magnetic disk may generate enough magnetic flux through the first and second ferromagnetic workpieces 102', 102 "to lift both ferromagnetic workpieces 102', 102". However, it may be desirable to separate the first ferromagnetic work piece 102' from the second ferromagnetic work piece 102 ". In these examples, a second magnetic disk that is weaker than the first magnetic disk and that only produces enough magnetic flux through the ferromagnetic workpiece 102 to lift the first ferromagnetic workpiece 102' may replace the first magnetic disk.

In the illustrated embodiment, the bottom 128A of the actuator 128 is coupled to the housing 110 using one or more screws 162. Thus, the bottom 128A acts as a cover for the housing 110. In addition, the ferromagnetic piece 148 is coupled to the bottom 128A of the actuator 128 using one or more screws 162. In this way, when the magnetic disk 112 and the non-ferromagnetic mounting plate 132 are moved to the upper portion of the housing 110 and the magnetic coupling apparatus 100 is in the first open position, the magnetic disk 112 and the non-ferromagnetic mounting plate 132 are disposed adjacent to the ferromagnetic piece 148 and/or in contact with the ferromagnetic piece 148. A magnetic circuit is then formed from the N-pole portion 116 of the magnetic disk 112 through one of the ferromagnetic plates 148, through the non-ferromagnetic mounting plate 132, through the other ferromagnetic plate 148 and to the S-pole portion 116 of the magnetic disk 112. This loop results in a number of advantages of the magnetic coupling 100, as discussed above.

As shown, the non-ferromagnetic mounting plate 132 is coupled to the interface 130 by screws 166. The joint 130 includes a first portion 130A and a second portion 130B, wherein in at least some embodiments the first portion 130A has a smaller cross-sectional area than the second portion 130B. In at least one embodiment, the first portion 130A extends through a channel 168 in the bottom 128A and is coupled to the non-ferromagnetic mounting plate 132 via screws 166. Due to the coupling of the engagement portion 130 to the non-ferromagnetic mounting plate 132, translation of the engagement portion 130 along the vertical axis 120 will translate the non-ferromagnetic mounting plate 132 and the magnetic disk 112 along the vertical axis 120.

To translate the engagement portion 130 along the vertical axis 120, the actuator 128 may be pneumatically actuated. For example, the housing 128B of the actuator may include a port 174, the port 174 including a first port 174A and a second port 174B. As air is provided into the port 174A via an air compressor or otherwise, the pressure within the housing 128B of the actuator above the second portion 130B increases, which causes the joint 130 to move downward along the vertical axis 120. Translation of the engagement portion 130 causes the magnetic disk 112 to move downward along the vertical axis 120 such that the magnetic coupling 100 transitions from the first disconnected state to the second conductive state or the third conductive state or from the third conductive state to the second conductive state. To confine air provided into the port 174A within the housing 128B of the actuator and over the joint 130, the actuator 128 may include a cover (not shown) secured to the housing 128B of the actuator via one or more screws 176. Additionally or alternatively, air may be drawn from the port 174B to reduce the pressure below the second portion 130B relative to the pressure above the second portion 130B, which causes the joint 130 to move downward along the vertical axis 120.

Conversely, when air is provided into port 174B, the pressure within the housing 128B of the actuator below the second portion 130B increases, which causes the plate to move upward along the vertical axis 120. Translation of the engagement portion 130 causes the magnetic disk 112 to move upward along the vertical axis 120 such that the magnetic coupling apparatus 100 transitions from the second conductive state to the third conductive state or the first disconnected state or from the third conductive state to the first disconnected state. Additionally or alternatively, air may be drawn from the port 174A to reduce the pressure above the second portion 130B relative to the pressure below the second portion 130B, which causes the joint 130 to move upward along the vertical axis 120.

In at least some other embodiments, ports 174A, 174B may be formed through housing 110 and may apply pressure to the top of magnetic disk 112 or the bottom of magnetic disk 112 or reduce pressure to translate magnetic disk 112 along vertical axis 120.

Fig. 5 and 6 show top cross-sectional views of the magnetic coupling of fig. 1A-1B in different positions on a ferromagnetic workpiece 102. Referring to FIG. 5, a magnetic disk 112 is shown on a ferromagnetic workpiece 102'. As shown, the entire footprint of the magnetic disk 112 has been placed on the ferromagnetic workpiece 102'. As used herein, the term footprint may be defined as the surface area of the magnetic disk 112, i.e., width 180 times height 182. The entire footprint of the magnetic disk 112 is preferably placed on the ferromagnetic work piece 102 'because the maximum amount of flux will be transferred from the magnetic disk 112 to the ferromagnetic work piece 102'. The magnetic coupling apparatus 100 may be configured to elevate the footprint area of the magnetic disk 112 by greater than or equal to 22.0 grams of the ferromagnetic workpiece 102 per square millimeter when the entire footprint of the magnetic disk 112 is placed on the ferromagnetic workpiece 102'.

Although it is preferable to have the entire footprint of the magnetic disk 112 placed on the ferromagnetic work piece 102', the magnetic disk 112 is often placed on the ferromagnetic work piece 102' as shown in FIG. 6. This may occur when the magnetic coupling apparatus 100 is attached to an end of an arm unit of a robotic system, such as robotic system 600 (of fig. 14), wherein placement of the magnetic disk 112 on the ferromagnetic workpiece 102' is performed using determined positions of the magnetic coupling apparatus 100, computer vision, and/or some other automated process.

In the case where the magnetic disk 112 is placed on the ferromagnetic workpiece 102' as shown in fig. 6, the configuration of the magnetic disk 112 may provide some advantages. In particular, the magnetic disk 112 is less likely to delaminate from the ferromagnetic work piece 102 'when the magnetic disk 112 lifts the ferromagnetic work piece 102' as compared to other magnetic coupling devices. That is, since the plurality of permanent magnet portions 114 are included in the magnetic disk 112, when the magnetic disk 112 is placed on the ferromagnetic work piece 102 'as shown in fig. 6, only the leftmost permanent magnet portion 114 leaves the ferromagnetic work piece 102'. Thus, five other magnetic circuits are still formed between the magnetic disk 112 and the ferromagnetic work piece 102'. Thus, the magnetic disk 112 can still operate at a load of about 83% (5/6=. 83). In contrast, if the magnetic disk 112 includes only one permanent magnet portion 114, one third of the magnetic circuit will not be formed through the ferromagnetic work piece 102 'since 1/3 of the poles are away from the ferromagnetic work piece 102'. Thus, the magnetic disk 112 may operate at approximately 66% load. As another example, where the magnetic disk has a circular footprint including one or more north poles and one or more south poles and the magnetic disk is only partially placed on the ferromagnetic work piece 102, a majority of one or more of the poles will be away from the ferromagnetic work piece 102, significantly reducing the retention of the magnetic disk.

As described above, the plate 106 may have spaced apart protrusions 108. Referring to fig. 7-13, exemplary portions of plate 106 and protrusion 108 that may be incorporated into the magnetic coupling of fig. 1A-1C.

Fig. 7 is a side view of a portion of an exemplary portion of a plate 200 that may be used as plate 106. The plate 200 includes a plurality of protrusions 206 disposed on a bottom 208 of the plate 200. Each protrusion 206 is separated by a recess 210. In addition, the plurality of protrusions 206 collectively form a workpiece contact interface 212 of the plate 200.

Because of the plurality of protrusions 206 included in the pole plate 200, the magnetic coupling including the pole plate 200 creates a stronger magnetic field near the workpiece contact interface 212 than a magnetic coupling having a pole plate that does not include the protrusions 206. The magnetic field generated near the workpiece contact interface 212 may be referred to herein as a shallow magnetic field. Further, by including a plurality of protrusions 206 on the plate 200, the magnetic coupling including the plate 200 creates a weaker magnetic field that is deeper away from the plate 200 than a magnetic coupling that does not include the protrusions 206. The magnetic field generated farther from the plate 200 is referred to herein as the far field or deep magnetic field generated by the plate 200. In other words, the magnetic coupling including the plate 200 with the protrusion 206 has a stronger retention near the workpiece contact interface 212 than the magnetic coupling including the plate with a flush continuous interface without the protrusion 206.

Because the protrusion 206 of the pole plate 200 facilitates generating a stronger shallow magnetic field and a weaker far field magnetic field, the magnetic coupling including the pole plate 200 may be used to better unstack the thin ferromagnetic workpiece 102 than a magnetic coupling having a pole plate without the protrusion 206. That is, a magnetic coupling that includes a plate that does not include the protrusion 206 may generate a stronger far field magnetic field that will cause a plurality of thin ferromagnetic pieces 102 to couple with the magnetic coupling. This is an undesirable result when attempting to obtain a single thin ferromagnetic workpiece 102 from a stacked array of thin ferromagnetic workpieces 102. Thus, instead of using a magnetic coupling that includes a plate that does not include the protrusion 206 to unstack the ferromagnetic work piece 102, a plate 200 that includes the protrusion 206 may be used.

In an embodiment, varying the width 214 of the protrusion 206 results in a different shallow magnetic field generated by the same magnetic coupling. For example, as the width 214 of the magnetic protrusion 206 increases, the shallow magnetic field decreases and the far field magnetic field increases. Thus, to generate a preferred shallow magnetic field for a particular ferromagnetic workpiece 102, the width 214 of the protrusion 206 may be within about +/-25% of the thickness of the ferromagnetic workpiece 102 to be destacked. For example, when the magnetic coupling is unstacking a 2mm thick ferromagnetic workpiece 102, the width 214 of the protrusion 206 may be approximately 2mm (e.g., 2mm +/-25%). In an embodiment, this will produce a strong shallow magnetic field at a depth of between 0mm and 2mm from the workpiece contact interface 212. However, in at least one embodiment, there may be limits for generating a preferred shallow magnetic field for some ferromagnetic workpieces 102 having a thickness less than the limits. That is, for ferromagnetic workpieces 102 having a thickness less than Xmm, a preferably shallow magnetic field may be generated by the protrusion 206 having a width 214 at the lower limit Xmm, but not less than the lower limit. That is, to generate a preferred magnetic field for a workpiece 102 having a thickness of 1/2 x mm, the width 214 of the protrusion 206 may be at a lower limit of x mm, rather than +/-25% of 1/2 x mm. However, if the thickness of the ferromagnetic work piece 102 is Xmm or greater, the width 214 may be approximately equal to the thickness of the ferromagnetic work piece 102 (e.g., +/-25%). Examples of the lower limit may be in the range of 0mm to 2 mm. However, this is merely an example and is not meant to be limiting.

In at least one embodiment, when the magnetic coupling device comprising the pole plate 200 is coupled with ferromagnetic workpieces 102 having different thicknesses, a pole plate 200 having a width 214 (which is an average of the thicknesses of the ferromagnetic workpieces 102) may be used to reduce the need to change the pole plate. However, similar to the above, a lower limit (e.g., 2.0 mm) may be applied such that if the average thickness of the ferromagnetic workpiece 102 is below the lower limit (i.e., < 2.0 mm), the width 214 may be configured as the lower limit (i.e., 2.0 mm).

In an embodiment, varying the depth 216 and/or width 218 of the recess 210 results in different shallow magnetic fields generated by the same magnetic coupling 100. In an embodiment, the depth 216 and/or width 218 of the recess 210 may be approximately the same as the width 214 of the protrusion 206 (e.g., +/-25%) in order to generate an appropriate shallow magnetic field for a particular ferromagnetic workpiece 102. For example, if the width 214 of the protrusion 206 is 2mm, the depth 216 and/or width 218 of the recess 210 may be approximately 2mm (e.g., 2mm +/-25%). In an embodiment, this will produce a strong shallow magnetic field at a depth of between 0mm and 2mm from the contact interface 212. However, similar to the above, there may be limits to generating a preferred shallow magnetic field for some ferromagnetic workpieces 102 having a thickness less than the limits. That is, for ferromagnetic workpieces 102 having a thickness less than Xmm, a preferably shallow magnetic field may be generated by a depth 216 and a width 218 that are at a lower limit Xmm but not less than the lower limit. That is, to generate a preferred magnetic field for a ferromagnetic workpiece 102 having a thickness of 1/2 x mm, the depth 216 and width 218 may be at a lower limit of x mm, rather than +/-25% of 1/2 x mm. However, if the thickness of the ferromagnetic work piece 102 is Xmm or greater, the depth 216 and width 218 may be approximately equal to the thickness of the ferromagnetic work piece 102 (e.g., +/-25%).

Similar to the above, when the magnetic coupling apparatus 100 including the pole plate 200 is coupled to ferromagnetic workpieces 102 having different thicknesses, the pole plate 200 having the depth 216 and/or width 218 of the recess 210 (which is an average of the thicknesses of the ferromagnetic workpieces 102) may be used to reduce the need to change the pole plate. Further, a lower limit (e.g., 2.0 mm) may be applied such that if the average thickness of the ferromagnetic workpiece 102 is below the lower limit (i.e., < 2.0 mm), the depth 216 and width 218 may be configured as lower limits (i.e., 2.0 mm).

The pole plate 200 may be releasably coupled with the magnetic coupling 100. Thus, when the protrusion 206 of the pole plate 200 does not have the proper width 214, depth 216, and/or width 218 for the ferromagnetic piece 102 to which the magnetic coupling apparatus 100 is coupled, the pole plate 200 may be replaced with a more proper pole plate 200.

Fig. 8 is a side view of a portion of another exemplary portion of a plate 300 that may be used as plate 106. Similar to the plate 200 depicted in fig. 7, the plate 300 includes a plurality of protrusions 306 disposed on a bottom 308 of the plate 300. Each protrusion 306 is separated by a recess 310. The plurality of protrusions 306 collectively form a workpiece contact interface 312 of the plate 300.

Similar to the above, changing the width 314 of the protrusion 306 and/or the depth 316 and/or the width 318 of the recess 310 results in different shallow magnetic fields generated by the same magnetic coupling 100. In an embodiment, to generate an appropriate shallow magnetic field for a particular ferromagnetic workpiece 102, the width 314 and/or depth 316 of the protrusion and/or width 318 of the recess 310 may be approximately the same (e.g., +/-25%) as the thickness of the ferromagnetic workpiece 102 to be coupled to the magnetic coupling apparatus 100. However, in at least one embodiment, there may be limits for generating a preferred shallow magnetic field for some ferromagnetic workpieces 102 having a thickness less than the limits. That is, for ferromagnetic workpieces 102 having a thickness less than Xmm, a preferred shallow magnetic field may be generated by a width 314, a depth 316, and/or a width 318 that are at a lower limit Xmm, but not less than the lower limit. That is, to generate a preferred magnetic field for a ferromagnetic workpiece 102 having a thickness of 1/2 x mm, the width 314, depth 316, and/or width 318 may be +/-25% at a lower limit of x mm instead of 1/2 x mm. However, if the thickness of the ferromagnetic workpiece 102 is Xmm or greater, the width 314, depth 316, and/or width 318 may be approximately equal to the thickness of the ferromagnetic workpiece 102 (e.g., +/-25%). Examples of the lower limit may be in the range of 0mm to 2 mm. However, this is merely an example and is not meant to be limiting.

Alternatively, when the magnetic coupling including the pole plate 300 is coupled with ferromagnetic workpieces 102 having different thicknesses, the pole plate 300 having a width 314, a depth 316, and/or a width 318 (which is approximately the average of the thicknesses of the ferromagnetic workpieces 102) may be used to reduce the need to change the pole plate. However, similar to the above, a lower limit (e.g., 2.0 mm) may be applied such that if the average thickness of the ferromagnetic workpiece 102 is below the lower limit (i.e., < 2.0 mm), the width 314, depth 316, and/or width 318 may be configured as the lower limit (i.e., 2.0 mm).

Referring to fig. 9, the recesses 310 between the protrusions 306 may have a continuous ramp profile at their upper extremities (the ramp being defined at all points, without sharp corners). The curved recess 310 may transfer a higher magnetic flux to the ferromagnetic workpiece 102 than a magnetic coupling device comprising plates with sharp angled recesses. In an embodiment, to provide high magnetic flux transfer, the radius of curvature 324 of the curved recess 310 may be approximately 1/2 of the width 318 of the recess 310. Test data shows that by including a ramp profile for recess 310 that is 1/2 of the width 318 of recess 310, an improvement of greater than 3% can be obtained.

Fig. 10 is a side view of a portion of another exemplary plate 400 that may be used as plate 106. Similar to the plates 200, 300 depicted in fig. 6 and 7, respectively, the plate 400 includes a plurality of protrusions 406 disposed on a bottom 408 of the plate 400. Each protrusion 406 is separated by a recess 410. The plurality of protrusions 406 collectively form a workpiece contact interface 412 of the plate 400.

Similar to the above, changing the width 414 of the protrusion 406 and/or the depth 416 and/or the width 418 of the recess 410 results in different shallow magnetic fields generated by the same magnetic coupling 100. In an embodiment, the width 414 of the protrusion 406 and/or the depth 416 and/or width 418 of the recess 410 may be approximately the same as the thickness of the ferromagnetic workpiece 102 (e.g., +/-25%) in order to generate an appropriate shallow magnetic field for a particular ferromagnetic workpiece 102. However, in at least one embodiment, there may be limits for generating a preferred shallow magnetic field for some ferromagnetic workpieces 102 having a thickness less than the limits. That is, for ferromagnetic workpieces 102 having a thickness less than Xmm, a preferably shallow magnetic field may be generated by a width 414, depth 416, and/or width 418 that are at a lower limit Xmm but not less than the lower limit. That is, to generate a preferred magnetic field for a ferromagnetic workpiece 102 having a thickness of 1/2 x mm, the width 414, depth 416, and/or width 418 may be +/-25% at a lower limit of x mm instead of 1/2 x mm. However, if the thickness of the ferromagnetic work piece 102 is Xmm or greater, the width 414, depth 416, and/or width 418 may be approximately equal to the thickness of the ferromagnetic work piece 102 (e.g., +/-25%). Examples of the lower limit may be in the range of 0mm to 2 mm. However, this is merely an example and is not meant to be limiting.

Alternatively, when the magnetic coupling including the pole plate 400 is coupled with ferromagnetic workpieces 102 having different thicknesses, the pole plate 400 having a width 414, a depth 416, and/or a width 418 (which is an average of the thicknesses of the ferromagnetic workpieces 102) may be used to reduce the need to change the pole plate. However, similar to the above, a lower limit (e.g., 2.0 mm) may be applied such that if the average thickness of the ferromagnetic workpiece 102 is below the lower limit (i.e., < 2.0 mm), the width 414, depth 416, and/or width 418 may be configured as the lower limit (i.e., 2.0 mm).

In an embodiment, the plate 400 may further include compressible members 420 disposed between the protrusions 406 in the recesses 410. In an embodiment, the compressible member 420 compresses when the magnetic coupling 100, including the pole plate 400, is coupled with the ferromagnetic workpiece 102. Due to the compression of the compressible member 420, a static friction is created between the compressible member 420 and the ferromagnetic work piece 102 that may be greater than the static friction between the protrusion 406 and the ferromagnetic work piece 102. In this way, the ferromagnetic work piece 102 coupled with the magnetic coupling apparatus 100 including the pole plate 400 is less likely to rotate and translate than if the ferromagnetic work piece 102 were coupled with a pole plate that does not include the compressible member 420. In an embodiment, the compressible member 420 may be constructed of an elastic material, such as isoprene, polyurethane, nitrile rubber polymer, and/or the like.

Fig. 11A-11B depict another exemplary plate 500 that may be used as plate 106. Similar to the plates 200, 300, 400 depicted in fig. 7, 8, 10, the plate 500 includes a plurality of protrusions 502 disposed on a bottom 504 of the plate 500. Each protrusion 502 is separated by a recess 506. The plurality of protrusions 502 collectively form a workpiece contact interface 508 of the plate 500.

As shown, the workpiece contact interface 508 is non-planar. In an embodiment, the non-planar workpiece contact interface 508 may facilitate coupling the magnetic coupling apparatus 100 with a ferromagnetic workpiece having a non-planar surface. For example, the magnetic coupling 100 including the pole plate 500 may be used to couple the magnetic coupling 100 with one or more types of rods, shafts, etc. (e.g., camshafts). While the workpiece contact interface 508 includes a curved surface 510, the workpiece contact interface 508 may have any other type of non-planar surface. For example, the contour of the workpiece contact interface 508 may be similar to a ferromagnetic sheet to which a magnetic coupling device comprising the workpiece contact interface 508 is intended to couple.

Varying width 512 of protrusion 502 and/or depth 514 and/or width 516 of recess 506 results in different shallow magnetic fields generated by the same magnetic coupling, despite having a non-planar workpiece contact interface 508. In an embodiment, to generate an appropriate shallow magnetic field for a particular ferromagnetic workpiece 102, the width 512 of the protrusion 552 and/or the depth 514 and/or width 516 of the recess 506 may be approximately the same as the thickness of the ferromagnetic workpiece 102 (e.g., +/-25%). However, in at least one embodiment, there may be limits for generating a preferred shallow magnetic field for some ferromagnetic workpieces 102 having a thickness less than the limits. That is, for ferromagnetic workpieces 102 having a thickness less than Xmm, a preferred shallow magnetic field may be generated by a width 512, a depth 514, and/or a width 516 that is at a lower limit Xmm but not less than the lower limit. That is, to generate a preferred magnetic field for a ferromagnetic workpiece 102 having a thickness of 1/2 x mm, the width 512, depth 514, and/or width 516 may be +/-25% at a lower limit of x mm instead of 1/2 x mm. However, if the thickness of the ferromagnetic workpiece 102 is Xmm or greater, the width 512, depth 514, and/or width 516 may be approximately equal to the thickness of the ferromagnetic workpiece 102 (e.g., +/-25%). Examples of the lower limit may be in the range of 0mm to 2 mm. However, this is merely an example and is not meant to be limiting.

Alternatively, when the magnetic coupling including the pole plate 500 is coupled with ferromagnetic workpieces 102 having different thicknesses, the pole plate 500 having a width 512, a depth 514, and/or a width 516 (which is an average of the thicknesses of the ferromagnetic workpieces 102) may be used to reduce the need to change the pole plate. However, similar to the above, a lower limit (e.g., 2.0 mm) may be applied such that if the average thickness of the ferromagnetic workpiece 102 is below the lower limit (i.e., < 2.0 mm), the width 512, depth 514, and/or width 516 may be configured as the lower limit (i.e., 2.0 mm).

Fig. 12A-12B depict another exemplary plate 550 that may be used as plate 106. Similar to the plates 200, 300, 400, 500 depicted in fig. 7, 8, 10, 11A-11B, the plate 550 includes a plurality of protrusions 552 disposed on a bottom 554 of the plate 550. Each projection 552 is separated by a recess 556. The plurality of protrusions 552 collectively form a workpiece contact interface 558 of the plate 550.

As shown, the workpiece contact interface 558 is non-planar. In an embodiment, the non-planar workpiece contact interface 558 may facilitate coupling the magnetic coupling 100 with a ferromagnetic workpiece having a non-planar surface. For example, a magnetic coupling including a pole plate 550 may be used to couple the magnetic coupling 100 to one or more edges, corners, etc. of a ferromagnetic workpiece. While the workpiece contact interface 558 includes two downwardly sloping surfaces 560 extending from a center point 562, the workpiece contact interface 558 can have any other type of non-planar surface. For example, the contour of the workpiece contact interface 558 may be similar to a ferromagnetic sheet to which a magnetic coupling device comprising the workpiece contact interface 558 is intended to be coupled.

Despite having a non-planar workpiece contact interface 558, varying the width 564 of the protrusion 552 and/or the depth 566 and/or the width 568 of the recess 556 results in different shallow magnetic fields generated by the same magnetic coupling. In an embodiment, to generate an appropriate shallow magnetic field for a particular ferromagnetic workpiece 102, the width 564 of the protrusion 552 and/or the depth 566 and/or width 568 of the recess 556 may be approximately the same as the thickness of the ferromagnetic workpiece 102 (e.g., +/-25%). However, in at least one embodiment, there may be limits for generating a preferred shallow magnetic field for some ferromagnetic workpieces 102 having a thickness less than the limits. That is, for ferromagnetic workpieces 102 having a thickness less than Xmm, a preferred shallow magnetic field may be generated by a width 564, depth 566, and/or width 568 that is at a lower limit Xmm, but not less than that lower limit. That is, to produce a preferred magnetic field of ferromagnetic workpiece 102 having a thickness of 1/2 x mm, width 564, depth 566, and/or width 568 may be within a lower limit of x mm rather than +/-25% of 1/2 x mm. However, if the thickness of the ferromagnetic work piece 102 is Xmm or greater, the width 564, depth 566, and/or width 568 may be approximately equal to the thickness of the ferromagnetic work piece 102 (e.g., +/-25%). Examples of the lower limit may be in the range of 0mm to 2 mm. However, this is merely an example and is not meant to be limiting.

Alternatively, when the magnetic coupling including the plate 550 is coupled with ferromagnetic workpieces 102 having different thicknesses, the plate 550 having a width 564, a depth 566, and/or a width 568 (which is an average of the thicknesses of the ferromagnetic workpieces 102) may be used to reduce the need to change the plate. However, similar to the above, a lower limit (e.g., 2.0 mm) may be applied such that if the average thickness of the ferromagnetic workpiece 102 is below the lower limit (i.e., < 2.0 mm), the width 564, depth 566, and/or width 568 may be configured as the lower limit (i.e., 2.0 mm).

Fig. 13 is a side view of a portion of an exemplary protrusion 206. As shown, each protrusion 206 may itself include a protrusion 206'. The protrusion 206 'may further increase the shallow magnetic field and decrease the far field magnetic field as compared to the case where the protrusion 206 does not include the protrusion 206'. In alternative embodiments, the protrusion 206 may not include the protrusion 206'.

Other features of the POLE plate are described in U.S. provisional patent application No.62/623,407 (volume No. MTI-0015-01-US-E), entitled magnetic lifting device with POLE pieces with spaced apart protrusions (MAGNETIC LIFTING DEVICE HAVING POLE SHOES WITH SPACED APART procections), filed on 1-29, the entire contents of which are expressly incorporated herein by reference.

In view of the foregoing disclosure to validate fig. 7-13, the following average separation forces for different types of plates 106 are provided in the following table.

Referring to fig. 14, an exemplary robotic system 600 is shown. Although a robotic system 600 is depicted in fig. 14, the embodiments described in connection therewith may be applied to other types of machines (e.g., cranes, pick-and-place machines, robotic fixtures, etc.).

The robotic system 600 includes the electronic controller 136. The electronic controller 136 includes additional logic stored in an associated memory 142 for execution by the processor 140. Including a robotic movement module 602 that controls movement of a robotic arm 604. In the illustrated embodiment, the robotic arm 604 includes a first arm segment 606 that is rotatable about a vertical axis relative to the base. The first arm segment 606 is movably coupled to the second arm segment 608 by a first joint 610, and the second arm segment 608 is rotatable in a first direction relative to the first arm segment 606 at the first joint 610. The second arm segment 608 is movably coupled with the third arm segment 611 by a second joint 612, at which second joint 612 the third arm segment 611 is rotatable in a second direction with respect to the second arm segment 608. The third arm segment 611 is movably coupled to the fourth arm segment 614 by a third joint 616 and a rotational joint 618, the fourth arm segment 614 being rotatable relative to the third arm segment 611 at the third joint 616 in a third direction, the orientation of the fourth arm segment 614 relative to the third arm segment 611 at the rotational joint 618 being changeable. The magnetic coupling 100 is illustratively shown secured to an end of a robotic arm 604. The magnetic coupling apparatus 100 is used to couple a ferromagnetic workpiece 102 (not shown) with a robotic arm 604.

In one embodiment, the electronic controller 136, by the processor 140 executing the robotic movement module 602, moves the robotic arm 604 to a first pose at which the magnetic coupling apparatus 100 contacts the ferromagnetic workpiece 102 at the first position. The electronic controller 136, executing the control logic 144 via the processor 140, instructs the magnetic device 100 to transition from the first off state to the second on state or the third on state to couple the ferromagnetic workpiece 102 with the robotic system 600. The electronic controller 136 executes the robotic movement module 602 via the processor 140 to move the ferromagnetic workpiece 102 from the first position to the desired spaced apart second position. Once the ferromagnetic workpiece 102 is in the desired second position, the electronic controller 136 instructs the magnetic coupling apparatus 100 to transition from the second on state to the first off state to decouple the ferromagnetic workpiece 102 from the robotic system 600 by the processor 140 executing the control logic 144. The electronic controller 136 then repeats the process to couple, move, and decouple another ferromagnetic workpiece 102.

In an embodiment, the control logic 144 may also determine the presence, absence, or other characteristics of the ferromagnetic workpiece 102 relative to the magnetic coupling apparatus 100. To this end, the magnetic coupling 100 may comprise one or more magnetic field sensors. Referring to fig. 15, a representative top cross-sectional view of a magnetic coupling 100 including a magnetic field sensor 702 is shown. As described herein, the magnetic field sensors 702 are positioned such that a first magnetic field sensor 702A is positioned in a left half 704 of the magnetic coupling apparatus 100 and a second magnetic field sensor 702B is positioned in a right half 706 of the magnetic coupling apparatus 100. In addition, a third magnetic field sensor 702C is positioned in the front half 708 of the magnetic coupling apparatus 100, and a fourth magnetic field sensor 702D is positioned in the rear half 710 of the magnetic coupling apparatus 100. Front half 708 includes a first portion 712 of left side half 704 and a first portion 714 of right side half 706. The rear half 710 includes a second portion 716 of the left half 704 and a second portion 718 of the right half 706. The addition of the third and fourth magnetic field sensors 702C, 702D provides additional sensor values that may be used to determine different operating states of the magnetic coupling apparatus 100. For example, based on the outputs of the four magnetic field sensors, the control logic 144 may determine the orientation of the workpiece contact interface 104 relative to the ferromagnetic workpiece 102 on two axes of rotation, such as tilting from left to right and tilting from front to back.

And then to a function block of control logic 144. The simplest information required about the magnetic coupling apparatus 100 is information about the switching state of the magnetic coupling apparatus 100, i.e. a cell in a first off state, a second on state or a partially on state (e.g. a third on state). In the first open state, the magnetic coupling 100 has little or no leakage flux. In the second on state, the leakage flux of the magnetic coupling 100 is significantly more than in the first off state, even on a near perfect magnetic work circuit with the ferromagnetic workpiece 102. Thus, during calibration, readings of one or more of the magnetic field sensors 702 in the off state of the magnetic coupling 100 may be stored as calibration or hard-coded values in a memory 142 (see fig. 15) associated with the processor 140 of the control logic 144, and when the magnetometer readings rise above the first off state value or some offset above the off state value, the magnetic coupling 100 may be considered to be in a second on state or partially on state, such as a third on state. The magnetic coupling 100 may be considered to be in the first open state when the magnetometer readings are at or near the calibrated stored value. In an embodiment, through a calibration process, readings of one or more of the magnetic field sensors 702 in a desired partially conductive state may be stored in the memory 142 as calibration values or hard coded values, and when a magnetometer reading rises to or within a certain percentage of a particular stored reading, the magnetic coupling 100 may be considered to be in a corresponding partially conductive state, such as a third conductive state. In some embodiments, the magnetic field sensor 702 may be supplemented by one or more position sensors for determining the position of the magnetic disk 112 to calibrate the magnetic coupling apparatus 100.

When the magnetic coupling 100 is in the on state, another functional block of the control logic 144 may be used to determine whether the ferromagnetic workpiece 102 is present only under the left half 704, only under the right half 706, or under both the left half 704 and the right half 706. When there is no target component to which the magnetic coupling apparatus 100 is magnetically attached (see fig. 16), there is no "real" (i.e., external working) magnetic circuit through the pole plate 106 (see fig. 1B). Assuming that any workpiece 102 is sufficiently spaced from the pole plate 106 so as not to distort the magnetic field, the flux will extend through the air between the pole portions 116 (of fig. 1B), effectively representing leakage flux. This also results in a high leakage flux at the magnetic field sensor 702. In normal operation of the magnetic coupling 100, by storing this "maximum leakage flux" in the memory 142 associated with the processor 140 of the control logic 144 for a given second or partially conductive state (such as a third conductive state) (the leakage flux is either hard coded (given this value will be constant) or from calibration operation), it may be determined whether the ferromagnetic workpiece 102 is present by placing the magnetic coupling 100 in the second or partially conductive state (such as the third conductive state) corresponding to the stored "maximum leakage flux" reference value and comparing the current sensor output to the stored "maximum leakage flux" reference value for the conductive state or partially conductive state.

In addition to detecting the presence or absence of the workpiece 102, the control logic 144 may also provide an indication of the spacing of the workpiece contact interface 104 from the workpiece 102 when the presence of the ferromagnetic workpiece 102 is detected (current sensor value below the "maximum leakage flux" stored for presence detection). In an embodiment, the control logic 144 is configured to determine whether the workpiece contact interface 104 is proximate to the ferromagnetic workpiece 102. In one example, when the current value of the corresponding sensor 702 falls below a threshold value, the control logic 144 determines whether the workpiece contact interface 104 is proximate to the workpiece 102. The threshold value may be determined during a calibration run and stored in the memory 142 and may correspond to a known interval between the workpiece contact interface 104 and the workpiece 102 (see fig. 17). In one embodiment, a plurality of thresholds are stored on memory 142, each corresponding to a respective known interval. The plurality of stored thresholds allows the control logic 144 to provide a better approximation of the spacing between the workpiece contact interface 104 and the workpiece 102 and to distinguish a first spacing (see fig. 17) from a second, smaller spacing (see fig. 18). One advantage is that the ability to accurately determine the proximity of the workpiece allows the robotic system 600 (see fig. 14) to move at a higher speed until the magnetic coupling unit 100 is within a first interval from the workpiece 102 and then move at a lower speed until it is in contact with the workpiece 102. In an embodiment, for the various calibration runs and values discussed herein, separate calibration runs or values are performed for different types of ferromagnetic materials due to the fact that the target sensor readings may differ based on the respective size, shape, material, etc. of the target ferromagnetic workpiece.

In an embodiment, the control logic 144 is configured to determine the orientation of the first and second workpiece contact interfaces relative to the ferromagnetic workpiece 102. In one example, the orientation of the left half 704 of the workpiece contact interface 104 and the right half 706 of the workpiece contact interface 104 relative to the ferromagnetic workpiece 102 is determined by comparing the output of the first magnetic field sensor 702A and the output of the second magnetic field sensor 702B. When the output of the first magnetic field sensor 702A and the output of the second magnetic field sensor 702B meet the first criteria, a first spacing between the left half 704 of the workpiece contact interface 104 and the ferromagnetic workpiece 102 and a second spacing between the right half 706 of the workpiece contact interface 104 and the ferromagnetic workpiece 102 are determined by the control logic 144 to be substantially equal. In one example, the first criterion is that the output of the first magnetic field sensor 702A is within a threshold amount of the output of the second magnetic field sensor 702B. An example threshold amount is an absolute difference. In another example, the threshold amount is a percentage difference. When the first criterion is met, the left side half 704 and the right side half 706 of the workpiece contact interface 104 have substantially equal spacing relative to the workpiece 102 (see fig. 18). When the first criterion is not met, the left hand half 704 and the right hand half 706 of the workpiece contact interface 104 are angled relative to the workpiece 102 (see fig. 19). If third and fourth magnetic field sensors are incorporated, such as shown in FIG. 15, the angle about the pitch axis may be determined in addition to the angle about the roll axis depicted in FIG. 19 (see FIG. 20). Additionally or alternatively, the incorporation of a three-dimensional magnetic flux sensor may determine an angle about the pitch axis (see fig. 20) and/or an angle about the roll axis depicted in fig. 19.

In addition to these device status and workpiece detection capabilities, the presence and specific location of at least two magnetic field sensors 702 in a designated location on the pole plate 106 provides a more advanced feedback. This is because the situation-dependent possible uneven distribution of leakage flux around the individual poles 116 of the pole plate 106 can be sampled, compared and evaluated.

In an embodiment, in the second conductive state of the magnetic coupling 100 (the same applies to the known partially conductive state), if the left half 704 of the workpiece contact interface 104 of the pole plate 106 has good contact with the ferromagnetic workpiece 102, but the right half 706 of the workpiece contact interface 104 has poor contact with the workpiece 102 (see fig. 21), there will be more leakage flux on the right half 706 than the left half 704. The first magnetic field sensor 702A above the left half 704 and the second magnetic field sensor 702B above the right half 706 are able to detect this, and the sensor 702B above the right half 706 will return a higher reading than the sensor 702A above the left half 704. In one example, a bi-directional hall effect sensor is used for the sensor 702. Thus, by reading each sensor 702 separately and comparing the readings between them, the control logic 144 can determine that the right half 706 has poor contact on the workpiece 102. In an embodiment, the control logic 144 has functional blocks that can be implemented in hardware and microprocessor software to perform such evaluations. In one example, when the difference in the readings of sensor 702A and sensor 702B exceeds a stored threshold amount, control logic 144 determines that right half 706 has poor contact. In another example, when the difference between the reading of sensor 702B and the known stored value is less than a threshold, control logic 144 determines that right half 706 has poor contact, where the known stored value may be determined during calibration of magnetic coupling 100.

In an embodiment, the control logic 144 is configured to determine whether the left half 704 of the workpiece contact interface 104 and the right half 706 of the workpiece contact interface 104 are positioned within the target area 802 on the ferromagnetic workpiece 102 relative to the ferromagnetic workpiece 102 (see fig. 22-24). In one example, when the output of the first magnetic field sensor 702A meets a first criterion and the output of the second magnetic field sensor 702B meets a second criterion, the placement of the left side half 704 of the workpiece contact interface 104 and the right side half 706 of the workpiece contact interface 104 relative to the ferromagnetic workpiece 102 within the target region 802 (fig. 22-24) of the ferromagnetic workpiece 102 is determined by the control logic 144. An exemplary first criterion is that the output of the first magnetic field sensor 702A is within a first range of magnetic flux values, and an exemplary second criterion is that the output of the second magnetic field sensor 702B is within a second range of magnetic flux values.

22-24, a target area 802 is shown. The workpiece 102 is shown as a sheet of material having a right end 804 and a left end 806. The target region 802 is a portion of the workpiece 102 between a first offset 808 from a right end 804 of the workpiece 102 and a second offset 810 from a left end 806 of the workpiece 102. In one example, as the magnetic coupling 100 approaches and/or exceeds the second offset 810, the leakage flux associated with the left half 704 of the workpiece contact interface 104 is higher than the leakage flux associated with the right half 706 of the workpiece contact interface 104, as the left half 704 of the workpiece contact interface 104 approaches the left end 806 of the workpiece 102. In a similar manner, as the apparatus 100 approaches and/or exceeds the first offset 808, the leakage flux associated with the right half 706 of the workpiece contact interface 104 is higher than the leakage flux associated with the left half 704 of the workpiece contact interface 104, as the right half 706 of the workpiece contact interface 104 approaches the right end 804 of the workpiece 102. Although shown as a linear target region 802, a two-dimensional target region 802 may be defined for the length and width of the ferromagnetic workpiece 102. In one example, a calibration run is performed in which the apparatus 100 is placed at each of the first limit 808 (see fig. 24) and the second limit 810 (see fig. 23), and the corresponding leakage flux values of the magnetic field sensors 702A, 702B at the two limits are stored in the memory 142. The two leakage flux values stored for the first limit position (see fig. 24) are stored in memory 142 as "limit position 1" (two values, one for each sensor 702A, 702B). The two leakage flux values stored for the second limit position (see fig. 23) are stored in memory 142 as "limit position 2" (two values, one for each sensor 702A, 702B). In an embodiment, the first range of the first criterion is a value between limit position 1 and limit position 2 for one of the magnetic field sensors 702A, 702B and includes limit position 1 and limit position 2 for one of the magnetic field sensors 702A, 702B, and the second range of the second criterion is a value between limit position 1 and limit position 2 for the other of the magnetic field sensors 702A, 702B and includes limit position 1 and limit position 2 for the other of the magnetic field sensors 702A, 702B. Assuming that the first range of values corresponds to the left half 704 of the workpiece contact interface 104 and the second range of values corresponds to the right half 706 of the workpiece contact interface 104, the control logic 144 determines that the left end of the magnetic coupling 100 is positioned outside the target area 802 when the second criterion is met and the first criterion is not met, and likewise that the right end of the magnetic coupling 100 is positioned outside the target area 802 when the first criterion is met and the second criterion is not met.

In an embodiment, the use (storage) of the "limit position 1 and limit position 2" calibration values on the memory 142 allows the device user to calibrate the ferromagnetic workpiece 102 present signal to be on only when a particular magnetic working circuit is formed (if calibrated to the same position) or within range of the magnetic working circuit (if calibrated to 2 different positions). The left side half 704 and right side half 706 of the workpiece contact interface 104 may either be equivalent to the "maximum leakage" position of limit position 1/2, or it may be outside of it in a larger leakage position. These calibrations are calibrations that allow for so-called Double Blank Detection (DBD) and part-specific or range-specific validation. The freedom of the left hand side half 704 and right hand side half 706 of the workpiece contact interface 104 outside the limit position is intended to give the user more freedom, especially if they fall near the edges on thinner steel plates.

In an embodiment, it is also possible to use this multi-sensor approach to provide additional device status data. In the above case, in addition to comparing only two sensor readings to determine the overall state of the magnetic coupling apparatus 100 and the presence or absence of the ferromagnetic workpiece 102 near the workpiece contact interface 104, by taking more differential and accurate magnetic field measurements from each sensor 702 as it approaches the ferromagnetic workpiece 102 (i.e., presence has been detected, but proximity has not yet been quantified) and calculating the value of the difference between the value of each sensor 702 signal and the magnetometer readings, it is possible to determine the orientation of the magnetic coupling apparatus 100 relative to the ferromagnetic workpiece 102, such as what angle the magnet holder comprising the apparatus 100 is at relative to the planar ferromagnetic workpiece 102.

Still further, with respect to a calibration run using the magnetic coupling 100 with predefined ferromagnetic workpieces 102 having known parameters (size, shape, material, etc.), and by storing evaluation loop data obtained from processing the sensor 702 output signals during the different calibration runs into the memory 142, the orientation and distance to the target surface of the ferromagnetic workpiece 102 with respect to the magnetic coupling 100 position can be fully determined even before the workpiece contact interface 104 contacts the ferromagnetic workpiece 102, particularly if additional magnetic field sensors are placed in positions other than the previously specified positions, as shown in fig. 15. Since the magnetic coupling 100 emits leakage flux in any state (even in the off state), a very sensitive sensor can respond to small changes in leakage flux emanating from the pole plate 106 at the sensor detection surface in the off state. When the magnetic coupling 100 in the off state or known partially on state is in proximity to the ferromagnetic workpiece 102, then a magnetometer that is sufficiently sensitive may indicate proximity to the component and may transmit a signal that is converted to a control signal for the robotic arm 604 as a "vision" for the robot that would otherwise be blind. As another example, a magnetometer that is sufficiently sensitive may assist the robotic arm 604, which robotic arm 604 may determine its two-dimensional position by determining only the distance between the magnetic coupling 100 and the ferromagnetic workpiece 102 (e.g., the depth therebetween). Accordingly, the robotic arm 604 may be programmed to slow down (e.g., linearly or non-linearly) as the magnetic coupling 100 approaches the ferromagnetic workpiece 102 to avoid collisions.

For example, assuming there are a total of four magnetometers, one at the flux sensing surface of the left half 704 of the workpiece contact interface 104 and one at the flux sensing surface of the right half 706 of the workpiece contact interface 104, as previously described, and two additional sensors at other locations, such as shown in FIG. 15, when the magnetic coupling 100 is moved toward the ferromagnetic workpiece 102 with one of the sensors 702 moved closer (in absolute terms) than the other, the density of the leaky flux lines near that sensor 702 will increase, concentrating themselves toward the ferromagnetic workpiece 102. When the magnetic coupling 100 is brought closer to the ferromagnetic workpiece 102 (without changing the spatial pose and translational direction of the magnetic coupling 100 coupled to the end of the arm of the robotic system 600), the flux lines will be more densely redistributed on the magnetic coupling 100, with the density of flux lines on the nearest sensor 702 inversely proportional to the distance between the sensor 702 and the ferromagnetic workpiece 102. This will produce a higher reading in the magnetometer on the proximity sensor 702. By comparing the near magnetometer outputs with the signals output from the other 3 magnetometers, and by evaluating this data, the position of the ferromagnetic workpiece 102 and the distance from the working surface of the magnetic coupling apparatus 100 can be known given the known spatial relationship between the sensor 702 and the working surface of the workpiece contact interface 104. As another example, one or more three-dimensional magnetometers may be used to determine how close the ferromagnetic workpiece 102 is to the working surface of the magnetic coupling apparatus 100.

Other functions may be enabled when the magnetic flux source is turned on and contact is established with the ferromagnetic work piece 102 when the output of the magnetometer of the magnetic coupling means 100 is accurately calculated. There is a direct relationship between the amount of magnetic flux in the working magnetic circuit and the amount of physical force that the working magnetic circuit is capable of withstanding, which in the case of the magnetic coupling device 100 corresponds to the payload of the device 100. Since the leakage flux from the permanent magnet depends on how much magnetic flux is "consumed" (i.e., constrained) in the main working circuit, there is a correlation between the leakage flux and the maximum payload that the magnetic coupling 100 can sustain. In one embodiment, the processor 140 of the control logic 144 is programmed with the appropriate formulas and may perform calibration operations such that the combined readings of the magnetometers on the magnetic coupling 100 may be used to derive a more accurate retention force of the magnetic coupling 100 than known devices. This may be used as (i) "safety checks" to ensure that the magnetic coupling apparatus 100 is able to lift the ferromagnetic workpiece 102 before being moved by the robotic system 600, (ii) that the magnetic coupling apparatus 100 is operating at full load, and/or (iii) that the magnetic coupling apparatus 100 operation is not damaged or degraded. Additionally or alternatively, these methods may be used for component specific inspection and/or inspection of the thickness range of the ferromagnetic workpiece 102.

In all these cases, the processor 140 of the control logic 144 is responsible for accepting input from each magnetometer of the magnetic coupling 100 and performing calculations and comparisons. The processor 140 then determines different device states based on these calculations. In an embodiment, the device 100 communicates the determined device status and feedback points to a robot controller (e.g., 136 of fig. 14). This is handled by 24V I/O or a communication module (not shown). Once feedback has been transmitted to the robot controller 136, the robot controller 136 can adjust the orientation and operation of the device 100 to address challenges or problems in operation.

It should be understood that the control logic 144 includes the necessary components for isolating, filtering, and amplifying the signals provided by the sensors for processing by the documenting processor 140 of the magnetic coupling 100.

Additional details and embodiments regarding sensing capabilities and SENSOR arrangements that may be incorporated into the magnetic coupling 100 are disclosed in PCT patent application No. PCT/US18/29786 entitled "magnetic coupling with at least ONE OF SENSOR arrangement and demagnetizing capabilities (MAGNETIC COUPLING DEVICE WITH AT LEAST ONE OF SENSOR ARRANGEMENT AND A DEGAUSS CAPABILITY)" filed on 2018, 4, 27, the entire contents OF which are expressly incorporated herein by reference.

Various modifications and additions may be made to the exemplary embodiments discussed without departing from the scope of the invention. For example, although the above embodiments refer to particular features, the scope of the invention also includes embodiments having different combinations of features and embodiments that do not include all of the above features. Accordingly, the scope of the present invention is intended to embrace all such alternatives, modifications and variances which fall within the scope of the appended claims, and all equivalents thereof.

Claims

1. A magnetic coupling apparatus for magnetically coupling with a ferromagnetic workpiece, comprising:

a housing having a channel defining a channel axis;

a magnetic disk supported by the housing, the magnetic disk being movable along the channel axis between a first position and a second position, the magnetic disk comprising a plurality of permanent magnet portions interposed between a plurality of ferromagnetic pole piece portions;

a workpiece contact interface supported by the housing and adapted to contact the ferromagnetic workpiece; and

a magnetic shunt supported by the housing and magnetically accessible from the channel, wherein a first magnetic circuit is formed by the magnetic disk and the magnetic shunt with the magnetic disk in the first position and a second magnetic circuit is formed by the magnetic disk and the ferromagnetic workpiece through a workpiece interface with the magnetic disk in the second position.